The present invention relates to a method cf assembling a wound round or cylindrical rotor of a vertical type adjustable speed hydroelectric rotating machine at its installation site such as, for example, a power house of a hydroelectric power plant.
Hydroelectric power plants are expected to accommodate peak electric loads of electric power supply networks s that it is necessary for electric rotating machines in the hydroelectric power plants to be operated both as a generator and a motor in dependence upon load conditions Moreover, it is necessary for the generator-motor to be speed-variable for expanding adjustable range of power generation during generator operation for facilitating a smooth or a continuous adjustment of pumping power during motor operation. Consequently, in hydroelectric power plants wound rotor type electric rotating machines are increasingly employed in place of or to replace conventional salient pole rotor type electric rotating machines for the hydroelectric power plants.
Hydroelectric power plants have been and are frequently constructed in relatively inaccessible areas such as, for example, mountain ranges or the like, so that transportation of the constituents of large capacity hydroelectric power plants completed in factories such as, for example, water turbines and electric rotating machines coupled thereto was often impossible and, for the most part, still is extremely expensive because of limitations of modes of transportation, such that components of allowable size for such as, for example, the water turbine and electric rotating machines were manufactured in factories, transported to the installation site, assembled and installed in the power houses of the hydroelectric power plants.
An assembling method for a salient pole rotor of a large capacity hydroelectric rotating machine in an installation site has been proposed wherein steel laminations were laminated around an upright spider with a rotor shaft to form a laminated rotor rim, with the laminated rotor rim being clamped between fixed steel plates by reamer bolts, and the magnetic poles or pole and coil assemblies being dovetailed, and with terminals of the respective magnetic poles being connected to the formed rotor body.
Unlike the conventional salient pole type rotor, in the wound type rotor, a great many field coil conductor bars must be slotted in the slots formed around the laminated rotor core and the ends thereof must protrude from the laminated core for enabling connection. Moreover, radial cooling ducts must be regularly interposed in the laminated rotor core along the axial direction thereof so that an axial length of the wound type rotor of the electric rotating machine inevitably increases in comparison with an axial length of the conventional salient pole type rotor having the same capacity and the same diameter, and for example, the axial length of a wound type rotor may be about 10 m.
When a new large capacity hydroelectric power plant is to be constructed at a location where assembling of the adjustable speed wound type rotor at the installation site is required, it is necessary to increase the height of the power house, or, more precise, the power house superstructure in comparison with a normal height for the conventional salient pole type rotor electric rotating machine, because the assembled, or completed wound type rotor must be lifted vertically and moved by a crane to an already installed stator assembly in an installation pit of the power house for insertion into the stator assembly. Accordingly, over all construction costs of such power plant are naturally increased.
When an already existing large capacity hydroelectric power plant employing a conventional salient pole rotor type electric rotating machine is, for example, to be remodeled by replacing the old salient pole type rotor for a new wound type rotor having the same type capacity and the same diameter, remodeling reconstruction of the existing power house is necessary including at least increased increasing a height of the existing power house.
If a remodeling or reconstruction of a salient pole rotor type electric rotating machine in an existing underground hydroelectric power plant is required, such remodeling is generally considered cost prohibitive because of the necessary remodeling or reconstruction of the power house or the existing underground hydroelectric power plant.
Moreover, assembly of the wound type rotor of the electric rotating machine requires considerable number of manual operations for forming the field coils as compared with the manual operations necessary for the salient pole type rotor. For example, a wound type rotor generally requires inserting insulated conductor bars into, for example, 300 or more core slots, connecting ends of the insulated conductor bars to form field coils having a predetermined number of poles, insulating the connected portions, binding with a binding wire, for example, a steel wire with a diameter of a few mm and a length of few hundred km, the coil end portions protruding from the rotor core for suppressing defamation due to the centrifugal force applied thereto during the electric rotating machine operation, and brazing the binding wire for integrating the terms thereof. Th large number of manual operations necessary reduce assembly efficiency and increase the number of safety problems in carrying out the necessary operations thereby creating an additional important problem to be considered when assembling a wound type rotor for an electric rotating machine in a power house of a hydroelectric power plant.